1. Field of the Invention
The present invention relates to a roller connector which is mounted on a steering device of an automobile and used as a means for electrical connection between such electrical devices as the steering device and an air-bag system provided in the vehicle body.
2. Description of Related Art
There has been proposed a roller connector for electrical connection between an electric device mounted on a steering device and an electrical device provided in the vehicle body.
The roller connector enables electrical connection between an electrical device mounted on the steering wheel which is a rotating body, and an electrical device mounted in the vehicle body which is a fixed body. Between the rotor section (movable housing) which is actuated to turn by the steering wheel and a case constituting the stator section (fixed housing) is housed, in a wound state, a flexible electrical cable or an optical fiber cable (hereinafter these cables are generally called the xe2x80x9cflexible cablesxe2x80x9d). The cable is secured at one end to the rotor section and at the other end to the stator section, thereby enabling electrical connection between the electrical devices by utilizing winding and unwinding of the flexible cable.
Referring to the accompanying drawings, a conventional roller connector will be explained.
FIG. 14 is a plan view showing the conventional roller connector. FIG. 15 is a side plan view showing the conventional roller connector. FIG. 16 is a plan view for explaining the conventional roller connector. And FIG. 17 is a sectional view taken along line 17xe2x80x9417 of FIG. 14.
A roller connector 100, as shown in FIG. 16, is comprised roughly of a fixed housing 101, a movable housing 102 rotatably connected to the fixed housing 101, first and second flat cables 103 and 104 which are flexible cables housed between the fixed and movable housings 101 and 102, and a moving body 105 rotatably disposed between the fixed and movable housings 101 and 102.
The fixed housing 101 is provided with a cylindrical outer cylinder portion 108, an annular bottom wall 107 provided at the end of the outer cylinder portion 108, and a round hole 107a (shown in FIG. 17) provided at the central part of the bottom wall 107. On the other hand, the movable housing 102 is provided with a cylindrical inner cylinder portion 109 and an approximately annular upper wall 106 located on one end of the inner cylinder portion 109. The outer cylinder portion 108 and the inner cylinder portion 109 are arranged coaxially, defining an annular housing section 110 between the outer and inner cylinders 108 and 109.
Inside of the housing section 110 is disposed the moving body 105, which has a ring-shaped rotating plate 111, a cluster of a plurality of rollers 112 pivotally supported on the rotating plate 111, and a circular hole, and is comprised of a pair of cylindrical fixed columns 113. The pair of fixed columns 113 is formed integrally with the rotating plate 111. Between one of the pair of fixed columns 113 and the rollers 112 is formed a first opening portion 114 through which the first flat cable 103 is inserted; and between the other of the pair of fixed columns 113 and the rollers 112 is formed a second opening 115 through which the second flat cable 104 is inserted.
The first and second flat cables 103 and 104 are belt-like cables each having a plurality of conductors, such as copper (Cu), extended on one side of a base film made of an insulating tape. The first flat cable 103 is indicated in black and the second flat cable 104, in white, for the sake of convenience. The outer ends of the first and second flat cables 103 and 104 are connected to the joint portion 116 on the fixed side which is fixed to the outer cylinder portion 108, being electrically led out of the fixed housing 101 through the joint portion 116 on the fixed side.
The inner ends of the first and second flat cables 103 and 104 are connected to the joint portion 117 on the movable housing 102, which is fixed to the inner cylinder portion 109, and are electrically led out of the movable housing 102 through the movable joint portion 117.
The roller connector 100 of the above-described constitution is used as a means for electrical connection of vehicle-mounted air-bag system and horn circuit by fixedly attaching the fixed housing 101 to the vehicle body (not shown) or the movable housing 102 to a steering wheel member (not shown), and also by connecting both ends of the first and second flat cables 103 and 104 to electrical devices on both the vehicle body side and the steering wheel side through the fixed and movable joint portions 116 and 117.
Next, the fixed housing 101 and the movable housing 102 of the conventional connector 100 will be explained in detail.
The fixed housing 101, as shown in FIG. 17, is made of a synthetic resin material and formed by a molding process. On the housing 101 are formed the cylindrical outer cylinder portion 108, and an approximately annular bottom wall 107 which intersects the axis of the outer cylinder portion 108 and located on one end side of the outer cylinder portion 108. At the central part of the bottom wall 107 is formed a round hole 107a. 
At a specific part of the outer edge portion of the bottom wall 107 are provided a plurality (e.g., four) mounting portions 107b protruding outwardly. The mounting portions 107b are provided with holes 107c. 
On the other hand the movable housing 102 is made of a synthetic resin material and formed by a molding process. The approximately annular upper wall 106, the cylindrical inner cylinder 109 projecting out to meet the upper wall 106 at right angles, and an electrical lead-through section 118 projecting out on the opposite side of the inner cylinder portion 109 in the vicinity of the outer peripheral portion of the upper wall 106 are formed in one body.
The circular hole at the central part of the inner cylinder 109 includes a large-diameter hole 109a on one end side and a small-diameter hole 109b on the other end side which is smaller in diameter than the large-diameter hole 109a. 
The electrical lead-through section 118 of the upper wall 106, surrounded with an approximately semicircular side wall, is integrally formed into a cylindrical form, and has a first side wall 118a of a flat shape formed on the axis side of the movable housing 102, a second side wall 118b of a curved shape opposite to the first sidewall 118a, and a pair of third side walls 118c, 118c (shown in FIG. 14) of a circular shape in opposite positions connecting the first and second side walls 118a and 118b. The surface of the second side wall 118b of the curved shape is formed into a shape along the outer peripheral edge of the upper wall 106 of the movable housing 102.
In the area (section) surrounded by the first, second and third side walls 118a, 118b and 118c are arranged a plurality of (e.g., five) terminals 119 made of an electrically conductive material and a plurality of (e.g., four) leads 120 (shown in FIG. 14). The leads 120 are extended (led) out of the electrical lead-through section 118 of the movable housing 102. The terminal 119 and the lead 120 are electrically connected by an appropriate means to the first and second flat cables 103 and 104 through the movable joint portion 117.
The terminal 119 is configured as a so-called connector portion.
The inner cylinder portion 109 of the movable housing 102 is arranged with the inner cylinder 109 inserted in the hole 107a formed in the fixed housing 101, thereby forming both the movable housing 102 and the fixed housing 101 into one body.
Next, the structure for mounting the roller connector 100 to the steering device will be explained.
FIG. 18 is a plan view explaining the mounting the conventional roller connector to the steering device.
The steering device, as shown in FIG. 18, is comprised mainly of a steering wheel member 121, a steering column member 127, a steering shaft 129, and the roller connector 100.
The steering wheel member 121 has an annular rim portion 122 and a plurality of (e.g., four spaced at 90-degree intervals) spoke members 123 radially arranged; the rim portion 122 being supported at one end with a space section provided at the center. Also provided is an approximately rectangular holding portion 124 for holding the other end of each of the spoke members 123.
The rim portion 122 is formed by molding or cutting a synthetic resin material or a wood material. The spoke member 123 is made of a metallic material, being formed into one body through a pressing or cutting process.
On the column member 127 is placed the bottom wall 107 of the fixed housing 101 of the roller connector 100, which is secured to the column member 127.
The steering shaft 129 is installed through the column member 127, the inner cylinder portion 109 of the roller connector 100, and the holding portion 124 of the steering wheel member 121; then the steering wheel member 121 and the steering shaft 129 are fixedly locked by a nut 130.
In this state, the electrical lead-through section 118 of the roller connector 100 is projectingly disposed in the space section of the steering wheel member 121 from between a pair of adjacent spoke members 123 of the steering wheel member 121; and a pair of the third side walls 118c, 118c of the electrical lead-through section 118 are located adjacently to, or in contact with, each spoke member 123. In other words, the electrical lead-through section 118 is disposed like directly held in between the pair of spoke members 123.
Next, operation of the conventional steering device will be described.
First, when the rim portion 122 of the steering wheel member 121 is turned for example clockwise (in the direction of the arrow A), each spoke member 123 is turned by the rotation of the rim portion 122. Then, with the rotation of the spoke member 123, the electrical lead-through section 118 of the roller connector 100 directly held in the pair of spoke members 123 is turned together.
With the rotary motion of the electrical lead-through section 118, the movable housing 102 of the roller connector 100 turns together.
That is, with the rotation of the rim portion 122, the movable housing 102 of the roller connector 100 turns clockwise by a predetermined number of turns.
On the other hand, the fixed housing 101 of the roller connector 100, being secured on the column member 127, is held in the secured status.
When the rim portion 122 is turned for example in the counterclockwise direction, the electrical lead-through section 118 of the roller connector 100 directly held between the pair of spoke members 123 is also turned together with nearly the same operation as stated above, thus causing the movable housing 102 of the roller connector 100 to turn counterclockwise by the predetermined number of turns.
In the steering device using the roller connector 100 of the above-described constitution, however, when the rim portion 122 is turned clockwise or counterclockwise, the electrical lead-through section 118 directly held between the spoke members 123 is turned together. At this time, the spoke member 123 made of a metallic material collides against the electrical lead-through section 118 made of a synthetic resin material, which, therefore, is pushed to turn after bumping against the electrical lead-through section 118.
Therefore, there occurs a knocking sound, which is annoying to the driver, when the spoke member 123 collides against the electrical lead-through section 118.
In view of these and other problems associated with the prior art, an object of the present invention is the provision of a roller connector which will not produce a knocking sound if the electrical lead-through section 118 of the roller connector 100 collides against the spoke member 123 of the steering wheel member 121 during the operation of the steering device.
The roller connector of the present invention is comprised of a fixed housing, a movable housing having an upper wall and an electrical lead-through section projecting out of the upper wall and rotatably mounted in the fixed housing, and a flexible cable housed in a space formed between the fixed housing and the movable housing. The flexible cable at least one end of is connected to the electrical lead-through section of the movable housing at the other end of the housing. Disposed adjacently to the electrical lead-through section of the upper wall is an elastic member, to thereby turn the movable housing by applying a driving force to the elastic member. Thanks to this configuration, therefore, the roller connector has such an advantage that a knocking sound will be absorbed by the elastic member even when the spoke member made of a metallic material knocks against the elastic member, thus producing no knocking sound.
The roller connector of the present invention is provided with a fixing post on the upper wall to thereby lock the elastic member, and therefore has the advantage that the elastic member can be reliably fixed.
Furthermore, in the roller connector of the present invention, the elastic member is locked on a side wall of the electrical lead-through section. Because of this configuration, it is possible to provide a low-cost roller connector which allows the mounting of the elastic member to the electrical lead-through section by a simple structure.
The roller connector of the present invention has a fixing post formed adjacently to the electrical lead-through section on the upper wall. The elastic member is locked to the fixing post and the electrical lead-through section. Because of this configuration, the elastic member is securely held by the above-described two members, enabling to keep stabilized arrangement of the elastic member for a prolonged period of time.
Furthermore, the roller connector of the present invention has, on the upper wall, a plurality of fixing posts formed, on which the elastic member is locked; because of this configuration, the elastic member is locked more reliably by these two fixing members.
Furthermore, the roller connector of the present invention is designed such that the elastic member is driven by the spoke member of the steering wheel member. Because of this configuration, it is unnecessary to separately form an elastic member driving member on the steering wheel member. Therefore a conventional spoke member is usable, thus enabling the provision of a steering device using the roller connector that is driven by a low-cost steering wheel member.